/*
 * This file contains code from "C++ Primer, Fourth Edition", by Stanley B.
 * Lippman, Jose Lajoie, and Barbara E. Moo, and is covered under the
 * copyright and warranty notices given in that book:
 *
 * "Copyright (c) 2005 by Objectwrite, Inc., Jose Lajoie, and Barbara E. Moo."
 *
 *
 * "The authors and publisher have taken care in the preparation of this book,
 * but make no expressed or implied warranty of any kind and assume no
 * responsibility for errors or omissions. No liability is assumed for
 * incidental or consequential damages in connection with or arising out of the
 * use of the information or programs contained herein."
 *
 * Permission is granted for this code to be used for educational purposes in
 * association with the book, given proper citation if and when posted or
 * reproduced.Any commercial use of this code requires the explicit written
 * permission of the publisher, Addison-Wesley Professional, a division of
 * Pearson Education, Inc. Send your request for permission, stating clearly
 * what code you would like to use, and in what specific way, to the following
 * address:
 *
 *  Pearson Education, Inc.
 *  Rights and Contracts Department
 *  75 Arlington Street, Suite 300
 *  Boston, MA 02216
 *  Fax: (617) 848-7047
*/

#ifndef QUEUE_H
#define QUEUE_H

//NB: if change the interface in this file, also update Queue_interface.h!!!!
//    and int-Queue.h

#include <iostream>
#include <list>

// declaration that Queue is a template needed for friend declaration in QueueItem
template <class Type> class Queue;
// function template declaration must precede friend declaration in QueueItem
template <class T>
std::ostream& operator<<(std::ostream&, const Queue<T>&);

template <class Type> class Queue
{
	friend std::ostream&
	operator<< <Type> (std::ostream&, const Queue<Type>&);
public:
	Queue() { }
public:
	// construct a Queue from a pair of iterators on some sequence
	template <class It> Queue(It beg, It end): items(beg, end) { }

	// replace current Queue by contents delimited by a pair of iterators
	template <class Iter> void assign(Iter beg, Iter end)
	{
		items.assign(beg, end);
	}

	// return element from head of Queue
	// unchecked operation: front on an empty Queue is undefined
	Type& front()
	{
		return items.front();
	}
	const Type& front() const
	{
		return items.front();
	}

	// add element to back of Queue
	void push(const Type& t)
	{
		items.push_back(t);
	}
	// remove element from head of Queue
	void pop()
	{
		items.erase(items.begin());
	}

	// true if no elements in the Queue
	bool empty() const
	{
		return items.empty();
	}
private:
	std::list<Type> items;
};

template <class Type>
std::ostream& operator<<(std::ostream& os, const Queue<Type>& q)
{
	os << "< ";
	typename std::list<Type>::const_iterator beg = q.items.begin();
	while (beg != q.items.end()) {
		os << *beg << " ";
		++beg;
	}
	os << ">";
	return os;
}

#endif

